Cartesian diver toy



Unite 3,@'Z7,697 Patented E 'eis. 19, 1953 line 3,tl77,697 CARTESEAN DIVER TfiY Carroll Brooks Fry, Santa Monica, Calif. (18259 Pacific oast Highway, Malibu, Calif.) Filed June 4-, i959, Ser. No. $38,648 13: Qiaims. (ill. id-4 2) This invention relates generally to toys, and more particularly to a so-called cartesian diver toy.

Broadly speaking, cartesian diver toys are very well known in the art and consist of a simulated aquatic figure which may be caused to rise and sink in a liquid filled chamber by varying the pressure of the liquid. Toys of this general character have been found not only to be highly intriguing to both adults and children but also to possess certain benefits as a visual educational device for children.

A broad object of the invention is to provide a cartesian diver toy which possesses certain novel features of construction and operation that enhance both its interest and its visual educational qualities.

A more specific object of the invention is to provide a cartesian diver toy of the character described in which the pressure adjusting means are designed to retain each pressure setting so as to permit retention of a simulated aquatic figure, or cartesian diver element, in a submerged position.

Another object of the invention is to provide a cartesian diver toy of the character described in which the liquid pressure may be varied over a given range to control the vertical movement of a cartesian diving element and wherein further this given pressure range may be adjusted to compensate for changes in external climactic conditions, changes in the buoyancy of the diving element, or other reasons which make it necessary to alter the pressure adjusting range of the toy.

Yet another object of the invention is to provide a cartesian diver toy of the character described which permits both coarse and fine adjustments of liquid pressure.

A further object of the invention is to provide a cartesian diver toy of the character described incorporating a plurality of cartesia-n diving elements which may be independently controlled in their vertical movement.

Yet a further object of the invention is to provide a cartesian diver toy which may be operated either at positive or negative pressure.

A further object of the invention is to provide a cartesian diver toy which may use both live sea life and replaceable aquatic scenes for pictorial backgrounds.

A still further object of the invention is to provide an improved cartesian diving element for a cartesiau diver toy of the character described, which element has a buoyant cartridge which may be inserted in any one of several difierent cartesian diving elements having various simulated shapes and which is adjustable to vary its positive buoyancy to suit the diving element in which it is inserted.

A still further object of the invention is to provide a cartesian diver toy of the character described possessing various novel features of construction, appearance and use which result in a toy possessing greatly increased entertainment and educational qualities.

Other objects, advantages and features of the invention will become readily apparent as the description proceeds.

Briefly stated, the objects of the invention are attained by the provision of a cartesian diver toy equipped with a transparent chamber filled with liquid, such as water. Submerged in this liquid are a plurality of cartesia-n diving elements having different simulated shapes, such as a simulated diver, a simulated sea chest, and a simulated diving bell.

Each of these diving elements contains a removable buoyant cartridge which normally affords the element with a positive buoyancy. These cartridges are identical for simplicity and economy of manufacture. Also, a single cartridge may be used on different diving elements.

Each cartridge includes a hollow, flexible portion which is sensitive to a variation in liquid pressure and achieves the well known cartesian diving efiect of a diving element sinking in response to an increase in the pressure of the surrounding liquid and rising in response to a decrease in the pressure of the surrounding liquid. The cartridge is adjustable to vary the buoyancy of the diving element in which it is installed.

The pressure of the liquid within the chamber of the present cartesian diver toy is adjusted by a pair of pressure adjusting members. One of these members constitutes a fine pressure adjusting means for controlling the vertical movement of the several diving elements. The other pressure adjusting member constitutes a coarse pressure adjusting means for shifting the pressure adjusting range of the fine adjusting means. The pressure adjusting members retain their adjusted pressure settings so as to permit retention of one or more of the diving elements in their submerged position, and may be set for operation of the toy either at positive pressure or negative pressure.

In use of the toy, the several diving elements are adjusted to have different buoyancies so as to permit adjustment of the liquid pressure to cause one element, such as the simulated diver, to rise and sink, while another element, such as the sea chest, remains at the bottom of the chamber. In the illustrative toy, the simulated diver carries the graple hook by which he may grasp the sea chest which may then be caused to rise to the surface with the diver, so as to simulate retrieving of the chest by the diver, by a decrease in the liquid pressure to a value which afiords the sea chest with a positive buoyancy. The buoyancy of the diving bell is set to be greater than that of the diver so as to be capable of controlled submergence, while the diver remains in a submerged posi tion, for effecting a simulated rescue of the diver.

The toy possesses various other novel features of design and use which will become readily apparent as the description proceeds.

The invention may be best understood from the following detailed description thereof, taken in connection with the annexed drawings, wherein:

FIG. 1 is a vertical section through the present cartesian diver toy;

FIG. la illustrates a modified pressure adjusting means for the toy;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is an enlarged detail of one of the cartesian diving elements of the present toy, with parts broken away for clarity;

FIG. 4 is a section through the replaceable buoyant cartridge embodied in the diving element of FIG. 3;

FIG. 5 is a detail, partially in section, of a replaceable simulated aquatic figure for use in the present toy; and

H6. 6 illustrates a modified form of the toy.

Referring now to these drawings, the present cartesian diver toy will be seen to comprise a sealed hollow chamber 16 to which is supported on a base 12. panel 14 of the chamber 19 is transparent. Located within the chamber It and bonded or otherwise joined to the walls of the chamber, is a generally horizontal partition 16.

The interior of chamber it), below the partition 16, is filled with a liquid 18, such as water. Partition 16 which is spaced at distance bel v t..e top wall 2% of the chamber, is designed to simulate the surface of a large body of Water, such as the ocean, and to this end may be rippled and colored a greenish-blue, if desired. To enhance the The front visual appearance of the toy, a sky scene and an underwater scene are painted or printed on a transparent card 22 which is removably inserted in a slot 24 at the rear of chamber 10. These scenes are visible from the front of the chamber, as shown in FIG. 1. Card 22 is removable to permit the background scenes to be changed. An artificial landscape 26 may be provided at one end of the partition 16 by cementing sand to the partition and placing simulated trees and a dwelling as shown. The simulated scenery above the surface is completed by a small ship 28, supported on the partition 16. This ship has certain novel features of construction which will be presently described. ,The simulated underwater scenery is completed by an uneven layer of sand 30 and a few small stones 32, sea shellsand the like cemented to the bottom wall 34 of the container 10.

In FIGS. 1 and 2, it will be'observed that the partition 16 slopes, upwardly toward the right and rear walls of the container. This slope'of the partition has a twofold advantage. First, in FIG. 1 it will be seen that the slope of the partition enhances the depth perception of the simulated scenery. Secondly, as will be presently more fully described, the slope of the partition promotes rnigration of any bubbles of air in the liquid 18 belowthe partition toward the right-hand end of the container and obscures such bubbles from view.

One feature of the present toy resides in the provision of a replaceableQaquatic FIGURE 38 such as the simulated shark illustrated in FIG. 1, or the simulated shark illustrated in FIG. 1, or the simulated octopus 40 illustrated in FIG. 5. To permit interchanging of the figures 38 and 40, the left-hand wall 42 of the chamber has an opening 44 of the size to pass the figures. The figures may be made of a suitable flexible material to enable projecting portions thereof to be deformed sufficiently to enable them to be inserted through the opening 44.

"Formed on the side wall 42 about the opening 44 is an externally threaded cylindrical flange 46 on which is threaded a removable closure or cap 48. Each ofthe figures 38 and 49 is supported on a circular plug 59 which has a sliding fit in the chamber opening 44. This plug has a circular flange 52 which is designed to seat on the outer circular edge of the chamber flange 46, in the manner illustrated in FIG. 1. When the cap 48 is threaded on the chamber flange 46, it forces the plug flange 52 against the chamber flange to secure the figure 38 or 40 in position, as well as seal the chamber opening 44. Figures 38 and 40 may thus be interchanged by removing the cap 43.

The right-hand wall 54 of the chamber 10 below the partition 16 is relatively thick, as illustrated at 54. Formed in this thick side wall 54 are a pair of bores 56 and 58 which open at their inner ends to the interior of the chamber 10. If desired, the bores 56 and 58 may be obscured from view through the transparent front wall 14 of the chamber 10 by an opaque suitably colored vertical partition 60 joined to the bottom, front and rear walls of the container 10 and partition 16. The partition 60 has one or more openings 62 which communicate space 64 to the right of the partition 60 to the main liquid filled space 66 of the chamber 10. Also, the front panel 14 between the partition 60 and right end of the chamber 10 and below the landscape 26 is rendered opaque in any suitable manner.

Slidably fitted in the bores 56 and 58 are a pair of pistons 66 and 68. These pistons are sealed to the walls of their respective bores by the O-rings 69 illustrated.

Piston 66 has a stem 70 threaded in the wall 54 of chamber 10 and extending to the exterior of the latter. This stem mounts a knurled handle 72. Similarly, piston 68 has a stem 74 threaded in the chamber wall 54 and extending to the exterior of the chamber. The stem mounts a knurled handle 76.

1 The bores and pistons just described provide a pair of pressure adjustingmeans for varying the pressure of the 4 liquid 18 to control vertical movement of the cartesian diving elements 78, 80 and S2 in the liquid. As will shortly be described, turning of the knurled handles 72 and 76 in one direction moves the pistons 66 and 68 to the left, as viewed in FIG. 1, to increase the liquid pressure and thereby decrease the buoyancy of the cartesian diving. elements in the well known manner. Turning of the handles 72 and 76 in the opposite direction moves the pistons to the right to decrease the liquid pressure and thereby increase the buoyancy of the diving element's. Other forms of pressure adjusting means may be used, of course.

A second novel feature of the present toy, which has the advantages hereinafter mentioned, resides in coarse and fine pressure adjustments afforded by the pistons 66 and 68. These coarse and fine adjustments are accomplished by making the pistons and their respective bores of different size, .as illustrated. Thus, a given longitudinal adjustment of the larger piston 66 efiects a material, such as a molded plastic.

greater pressure change than the same adjustment of the smaller piston '68. These same ends could be achieved, of course, in various ways, such as by making the pistons of the same size and providing their stems 70 and 74 with threads of different pitch, as shown in FIG. In.

As previously mentioned, and shown in FIG. 1, the three cartesian diving elements 78, 80 and 82 simulate, respectively, a diver, a diving bell and a sea chest. Each of these diving elements is made of suitable lightweight Removably inserted within each diving element is a buoyant cartridge 84 which, itself, forms a cartesian element. The three cartridges 84 are identical and removably inserted in their respective elements. This similarity of the cartridges 84 obviously reduces the cost of manufacture of the elements and is further desirable since a cartridge may be removed from one diving element and inserted in another should the cartridge in the other element become lost.

Because of the similarity of the cartridges 84 and their manner of attachment to the respective diving elements, a detailed description of only one diving element, namely, the simulated diver 78, is deemed necessary to a complete understanding of the invention. Referring to FIG. 4, the cartridge 34 will be seen to comprise a hollow shell 86 of suitable flexible plastic material. The walls forming the upper end of the shell 86, as the latter is viewed in FIG. 4, are relatively thin so as to be capable of inward deflection under an increase in external pressure, as indicated in dotted lines. The upper end of the shell is sealed off by a rigid interior wall 87.

The lower end of the shell has relatively thick Walls and is provided with a central opening 88. The lower end of this opening is internally threaded as shown.

Received within the opening 88 is a buoyancy adjusting member 90. This member includes a smooth walled upper portion 92 which has a close sliding fit in the upper smooth walled portion of the opening 38. Aseal ring 93 provides a liquid tight seal between the member and shell 86. The lower end of the member 90 has external threads which engage the internal threads on the shell 86, so that the axial position of the member 901 in the shell may be adjusted by rotation of the member in one direction or the other.

Referring now to FIG. 3, it will be seen that the cartridge 84 is inserted in a bore 94 formed in an opening to the exterior of the simulated diver 78. As mentioned, it is preferable that the cartridge be removable To this end, the cartridge may have a.

the other diving elements 80 and 82 has a replaceable buoyant cartridge 84. These latter .diving elements also have passages 96 through which the pressure of the liquid 18 may act on the flexible portion as of their respective buoyant cartridges. The arrangement is such that when the pressure adjusting means 72 and 76 are adjusted to the left in FIG. 1 to increase the pressure of the liquid 18, the increased liquid pressure acting on the flexible cartridge portions d6 tends to slightly collapse or compress the latter, as indicated in phantom lines in PEG. 4. This reduces the liquid displacement volume and hence the buoyant eiiect of the cartridges. When the pressure adjusting means are adjusted in the opp-osite direction to relieve the liquid pressure, the entrapped air in the cartridges expands the latter to their normal solid line condition of FIG. 4 and restores the normal liquid displacement volume and buoyant efiect to the cartridges.

it will be apparent from the drawings that the liquid displacement volume, and, therefore, the buoyancy of the diving elements 73, 8t) and 82, i.e., buoyant force of the liquid on the elements, may also be varied by adjustment of the buoyancy adjusting member 90 in the buoyant cartridge of the respective elements. Thus, when the member 9'0 in a given diving element is adjusted outwardly of its cartridge 84, the volume of liquid displaced by the diving element, and hence its positive buoyancy, are increased. Similarly, adjustment of the member 99 inwardly of its cartridge reduces the volume of liquid displaced by the diving element and hence its positive buoyancy.

One purpose of this adjustment is to enable the buoyancies of the diving elements to be changed to compensate for small variations in atmospheric pressure or temperature in diit'erent places where the toy may be used as well as for small changes in the weights of the diving elements during prolonged usage, resulting for example from the absorption of a slight amount of water by the elements. A second purpose for the buoyancy adjusting members 99 is to enable adjustment of the relative buoyancies or" the three diving elements so that they will rise and sink at different settings of the pressure adjusting means 72 and 76.

From this description, it is evident that the cartesian cartridge of each cartesian element 78, $0 and 82 aiiords the element with neutral buoyancy at a given liquid pressure related in part to the setting of the member 90, with positive buoyancy at liquid pressures less than this given pressure, and with negative buoyancy at liquid pressures greater than this given pressure so that they Will rise and sink as described. The liquid pressure at which the cartesian elements have neutral buoyancy may be changed by adjustment of the member 90. Thus the relative buoyancies of the elements 78, 8t} and 82 may be changed by adjusting the members 0.

A difference in the relative buoyancies of the three diving elements 78, 8b and 82, is desirable in the illustrated cartesian diver toy, for example, to permit Inanipulation of the toy to eilect a simulated retrieving of the sea chest 82 by the diver 7S, and a simulated rescue of the diver by the diving bell 86. To these ends, the diver 78 carries a hook 98 which is designed to engage in a ring 1% on the sea chest 82. Also, the buoyancy adjusting members 90 in the diver and sea chest are set so that at an intermediate setting of the pressure adjusting means 72, 74, the diver will possess just a very slight positive buoyancy and thus float in the liquid 18 and the sea chest 82 will possess a slight negative buoyancy and thus remain submerged, as illustrated in FIG. 1. If the pressure of the liquid 18 is now slightly increased by adjustment of the pressure adjusting means the diver 78 will acquire a negative buoyancy and sink to the bottom of the chamber ill.

Simulated retrieving of the sea chest by the diver is accomplished by tipping the chamber it slightly during the descent of the diver to direct the latter to position adjacent the sea chest wherein the grappling book 98 on the diver engages in the ring 166 on the sea chest. The

pressure in the chamber is now relieved by backing oil the pressure adjusting means to a position whereat both the diver and sea chest acquire a positive buoyancy. The diver will thus rise to the surface carrying the sea chest. Magnetic pick-up means on the diver and set chest may be employed, of course, in lieu of the grappling hook and ring arrangement described.

The buoyancy adjusting member 94 in the diving bell bit is set so that the latter will normally have a positive buoyancy greater than that or" the diver '78. During manipulation of the toy in the manner just mentioned, the diving bell 8% will remain at the surface of the liquid 38. The purpose of the diving bell is to effect a simulated rescue of the diver 78 from the simulated fish 33 or octopus To this end, the head or helmet portion 162 of the diver 78 carries a small plug of iron or other magnetically permeable material. Located within each or" the simulated sea animals 38 and so and the diving bell 88 is a small permanent magnet slug 1%.

During a descent of the diver '75 to the bottom of the chamber Ed, the diver may reach a position where he will be drawn toward the fish 38 by the magnetic attraction between the slug 11M in the diver and the magnet 1% in the fish. The diver will thus appear to be grasped by the fish. The liquid pressure in the container MD is now increased sufficiently to provide the diving bell $9 with a negative buoyancy. The diving bell will thus sink in the liquid 18.

During the descent of the diving bell, the chamber 10 is again tipped to direct the bell to a position over the diver who is now trapped by the fish 38. By properly manipulating the toy in this manner, the diving bell may be magnetically attached to the diver. The liquid pressure is then relieved until the diver and diving bell acquire a positive buoyancy suflicient to break the diver away from the fish. The diver and diving bell then rise in the liquid 18 to simulate a rescue of the diver from the fish. If desired, the diving bell 8% may carry hooks 198 for hooking the diver 78 to eifect the rescue in the manner just described.

As shown in FIG. 1, the simulated ship 28 has a cavity ill), opening to the underside of the partition 16, into which the diver '78 may rise. The dimensions of the cavity are such that when the diver is located in the cavity he is substantially obscured from View.

Ship 28 also has a simulated smoke stack 112. which opens at its lower end into the cavity lit; and registers at its upper end with an opening 14 in the top Wall 20 of the chamber it). Encircling this opening is an externally threaded, cylindrical flange 3.16 on the top wall 20 on which is threaded a removable closure or cap H8. The opening 114 forms a filling opening through which the liquid 18 may be poured into and removed from the chamber Ill. The cap 118 forms an air and liquid tight closure for the opening 114.

Threaded to the cap 118 is a small plug 32a having a central passage 122. When the plug 12% is completely tightened, as illustrated in FIG. 1, the central passage 122 is closed by the cap lid and the latter forms an airtight and liquid-tight closure for the opening 114, as just mentioned. The passage 122 may be exposed to atmosphere so as to vent the chamber Zltl, by unloosening the plug 12%. The purpose of the plug 12d and passage 122 is as follows.

It has been found by experience that cartesian diving elements, such as the diving elements '73, St} and 552 apparently tend to become slightly waterlogged after prolonged usage and often remain submerged even when the pressure in the chamber id is reduced to atmospheric pressure. It has been further found, however, that such waterlogged diving elements may be revived, that is, rendered positively buoyant so as to rise to the surface of the liquid 18, by producing a negative pressure in the chamber iii, that is a pressure less than atmospheric.

This negative pressure is created by first completely backing off the pressure adjusting means 72 and 76 and venting the chamber 10 by unloosening the plug 126. The pressure adjusting means 72 and 76 are then adjusted partially or completely to the left in FIG. 1. The plug 120 is then tightened to again seal the chamber 10, after which the pressure adjusting means 72 and 76 are backed off to create a slight vacuum, or negative pressure in the chamber 10.

The space above the partition 16 serves as a bubble trap and the partition is sloped to cause migration of any bubbles at the surface of the liquid 18 toward an opening in the partition 16. This opening is illustrated at 124 in FIG. 1. It will be seen that the opening is adjacent the vertical partition 6t) and the rear wall 22 of the chamber 10. As mentioned, the partition 16 slopes upwardly toward the rear wall 22 of the chamber. It will also be observed in the drawings that the partition if slopes upwardly toward the right-hand wall 54- of the chamber 19. Thus, in the normal position of the chamber It any bubbles at the surface of the liquid 13 tend to migrate toward the opening 124. The simulated smoke stack 112 has a small opening 126 through which the air above the partition may escape to the outside of chamber when the cap 116 is removed during filling of the chamber ail with the liquid 18.

A highly important feature of the invention resides in the dual pressure adjusting means 72 and '76. Thus, as previously mentioned, the pressure adjusting means 72 effects a coarse pressure adjustment and the pressure adjusting means 76 effects a fine pressure adjustment.

In use of the toy, the coarse pressure adjusting means is first adjusted to bring the pressure within the chamber 16 within the range of operation of the particular carte sian diving elements employed. The fine pressure adjusting means 76 is thereafter used to control the vertical movements of the elements in the liquid 18.

In the case of the illustrative diving elements 78, 3t) and S2, for example, the pressure adjusting means will be set as follows. The fine pressure adjusting means 76 is first set at an intermediate position. The coarse pressure adjusting means 72 is then adjusted to a position whereat the sea chest 82 has just a slight negative buoyancy so as to remain submerged and the diver 76 and diving hell 8 have positive buoyancies so as to float in the liquid 18, in the manner previously mentioned. The coarse pressure adjusting means is left in this position.

Subsequent adjustment of the fine pressure adjusting means 76 to the left of FIG. 1 so as to pressurize the liquid 18 will now cause sinking of the diver 78 and diving bell 38 in the manner previously described. Adjustment of the fine pressure adjusting means 76 to the right of its center position, of course, decreases the pressure of the liquid suiliciently to afford the sea chest with a positive buoyancy so that it will rise to the surface with the diver 78 during the simulated retrieving operation previously described. it will be apparent, in view of what has been said, that to permit control of the vertical movements of the several diving elements by the fine pressure adjusting means 76, the buoyancy adjusting members 90 in the several diving elements must be set so that the liquid pressures at which the various elements rise and sink fall within the range of pressure adjustment of the fine pressure adjusting means.

The present toy may, obviously, be operated with either negative or positive pressures in the chamber 10 if the cartesian diving elements are properly adjusted. A negative pressure condition is created in the chamber, in the manner described earlier, by threading the pressure adjusting means 72, '76 to their inner limit with the chamber vented and then backing off the means 72, 76 after the chamber vent is closed. Such negative pressure operation may be desirable to minimize the possibility of water leakage from the toy and damage to the latter. Excessive inward flexing of the chamber walls during negative pressure operation may be avoided by fixing one or more abutments 126 to the rear wall of the chamber in a position to engage the front chamber wall when the latter bows inwardly.

The toy maybe furnished with a live underwater scene by placing a tank 128 for tropical fish or the like directly behind the chamber 10. If such a tank is used, of course, the pictorial inserts 22 must be arranged so as to not entirely obscure the sea life in the tank.

In the modified toy of FIG. 6, a picture 130' containing a ship and other aquatic scenes is mounted on a partition 136 which extends across the chamber 10 and is spaced slightly from the front wall of the chamber. The chamher is filled with water until the water in the space between the front wall of the chamber and the partition 130 is at a level such that the pictured ship appears to be riding at the correct depth in the water. Because of surface tension and capillary effects, the surface of the water. in this narrow space tends to be uneven, simulating the surface of a large body of water.

The space behind the partition 130 serves as a bubble trap and also as a space into which the cartesian diving elements may rise. The elements may thus be made to appear to ascend into and descend from the ship pictured on the partition by causing them to rise to a position directly behind the ship.

It is possible that the toy might be sold in kit form. In this case, it might be desirable to provide the upper end of the chamber with a large opening, as shown in FIG. 6, to permit the placing of pieces in the chamber. This opening may be closed by a removable plug 132, for example. For negative pressure operation of the toy, it would not be necessary to positively attach the plug to the casing. For positive pressure operation, on the other hand, the plug should be firmly attached in some way to the casing so as to avoid the possibility of the plug being forced out of the chamber opening by the pressure in the chamber.

While, in the preceding description, the invention has been referred to as a toy, it will be apparent that the invention also serves as a unique visual educational device. Thus, the device may be used to acquaint a child with various forms of. sea life. Moreover, the described uses of the toy acquaints the child with various physical laws such as magnetism, the effect of variations in pressure, and underwater diving operations.

It will be apparent, therefore, that there has been described and illustrated a combined toy and visual educational device which is fully capable of attaining the objects and advantages preliminarily set forth.

While a preferred embodiment of the invention has been disclosed for illustrative purposes, numerous modifications in design and arrangement of parts are possible within the scope of the following claims.

I claim:

1. In a cartesian toy including a sealed, hollow chamber substantially filled with a liquid, and a cartesian element in said liquid which may be made to sink in said liquid by increasing the liquid pressure and to rise in said liquid by decreasing the liquid pressure, the improvements comprising pressure adjusting means on said chamber operable externally of the latter for varying the pressure of said liquid to make said element sink and rise, said pressure adjusting means including a first pressure adjusting member for initially setting the pressure of. said liquid at a given value at which said element has approximately neutral buoyancy in said liquid and a second pressure adjusting member for thereafter varying said pressure over a given range about said given value.

2. In a cartesian toy including a sealed, hollow chamber substantially filled with a liquid, and a cartesian element in said liquid which may be made to sink in said liquid by increasing the liquid pressure and to rise in said liquid by decreasing the liquid pressure. the improvements comprising pressure adjusting means on said chamber operable externally of the latter for varying the pressure of said liquid to make said element sink and rise, said pressure adjusting means including a first threaded pressure adjusting piston for initially setting the pressure of said liquid at a desired value at which said element has approximately neutral buoyancy in said liquid and a second threaded pressure adjusting piston for thereafter varying said pressure over a given range about said given value, said chamber having an opening through which the interior of the chamber may be vented, and a removable closure for sealing said opening, whereby at least one of said pistons may be advanced toward its maximum pressure setting when said closure is removed to vent the interior of the chamber and then retracted toward its minimum pressure setting after the closure has been replaced to create a pressure in the chamber which is less than atmospheric pressure.

3. In a cartesian toy including a sealed, hollow chamber substantially filled with a liquid, and a cartesian element in said liquid which may be made to sink in said liquid by increasing the liquid pressure and to rise in said liquid by decreasing the liquid pressure, the improvements comprising pressure adjusting means on said chamber operable externally of the latter for varying the pressure of said liquid to make said element sink and rise, said pressure adjusting means including a coarse pressure adjusting piston adjustable in a first cylinder in the Wall of said chamber for effecting coarse adjustments of liquid pressure and a fine pressure adjusting piston completely independent of said first piston and adjustable in a second cylinder in the wall of said chamber for effecting fine adjustments of liquid pressure.

4. In a cartesian toy including a sealed, hollow chamber substantially filled with a liquid, and a cartesian element in said liquid which may be made to sink in said liquid by increasing the liquid pressure and to rise in said liquid by decreasing the liquid pressure, the improvements comprising pressure adjusting means on said chamber operable externally of the latter for varying the pressure of said liquid to make said element sink and rise, said pressure adjusting means including a first threaded pressure adjusting piston for setting the pressure of said liquid at a given value and a second threaded pressure adjusting piston of approximately the same diameter as said first piston for varying said pressure over a limited range about said given value, said first pressure adjusting piston having coarse pitch threads so as to comprise a coarse pressure adjusting means and said second pressure adjusting piston having fine pitch threads so as to comprise a fine pressure adjusting means.

5. In a cartesian diver toy, a sealed hollow chamber substantially filled with a liquid, said chamber having normally vertical side walls and a bottom wall, one side wall oii said chamber having an opening above said bottom wall, a simulated aquatic figure extending to the interior of said chamber through said opening, and a removable closure sealing said opening and mounting said figure, said figure being removable through said opening for replacement by another simulated aquatic figure by removal 016 said closure.

6. In a cartesian diver toy including a sealed chamber substantially filled with a liquid, a cartesian diving element in said chamber which rises and sinks in said liquid in response to variations in liquid pressure, and pressure adjusting means on said chamber operable externally of the latter for varying the pressure of said liquid, the improvements comprising an internal transparent partition in said chamber which is approximately horizontal in the normal position of the chamber, and a simulated ship on said partition having a normally downwardly opening cavity which opens to the underside of said partition and into which said diving element may rise, the space below said partition being adapted to be completely filled with said liquid.

7. The subject matter of claim 6 wherein said partition slopes upwardly slightly toward one side wall of the container and is spaced from the top wall of the container, the normally highest point of said partition having an opening through which air in said space below the partition may escape to the space above the partition.

8. The subject matter of, claim 6 wherein said ship has a hollow simulated smoke stack which opens to said cavity and extends to the upper wall of said chamber, said upper wall having a liquid filling opening aligned with said stack, and a removable closure for said opening.

9. In a cartesian toy, a sealed chamber substantially filled with liquid, a cartesian element in said liquid, pressure adjusting means on said chamber operable exteriorly thereof for varying the liquid pressure on said element over a given range of pressures, said element including first pressure sensitive, variable liquid displacement means, the liquid displacement volume of which varies inversely with liquid pressure, and second manually adjustable, variable liquid displacement means, said first and second means affording said element with neutral buoyancy in said liquid at a given liquid pressure related in part to the setting of said second means, with positive buoyancy in said liquid at liquid pressures less than said given pressure, and with negative buoyancy in said liquid at liquid pressures greater than said given pressure, and said second means being adjustable to place said given pressure within said pressure range.

it). The subject matter of claim 9 wherein said second means comprises a member threaded on said element for adjustment into and out of said element.

11. In a cartesian to a sealed chamber substantially filled with liquid, at first cartesian element in said liquid including means which affords said element with neutral buoyancy at a first given liquid pressure on the element, with positive buoyancy at liquid pressures less than said given pressure, and with negative buoyancy at pressures greater than said given pressure, a second cartesian element in said liquid including means which atlords said second element with neutral buoyancy at a second given pressure difierent from said first given pressure, with positive buoyancy at pressures less than said second given pressure, and with negative buoyancy at pressures greater than said second given pressure, whereby said elements may be made to rise and sink in said liquid independently of one another by adjusting the liquid pressure, and means on said chamber operable exteriorly of the latter for adjusting the liquid pressure to make said elements rise and sink independently of one another.

12. The subject matter of claim 11 wherein at least one of said elements further includes means for adjusting the water displacement volume of the respective element to vary the liquid pressure at which the respective element has neutral buoyancy.

13. The subject matter of claim 11 wherein each of said elements further includes means for adjusting the water displacement volume of the respective element to vary the liquid pressure at which the respective element has neutral buoyancy.

References Qited in the file of this patent UNITED STATES PATENTS 460,810 Gunther Oct. 6, 1891 741,581 Humphrey Oct. 13, 1903 1,120,717 Hogan Dec. 15, 1914 1,838,215 De Clairmont Dec. 29, 1931 1,991,626 Rawdon Feb. 19, 1935 2,297,727 Svoboda et a1. Oct. 6, 1942 2,509,112 Seaman May 23, 1950 2,525,232 McGaughy Oct. 10, 1950 2,779,131 Scheithauer Ian. 29, 1957 

1. IN A CARTESIAN TOY INCLUDING A SEALED, HOLLOW CHAMBER SUBSTANTIALLY FILLED WITH A LIQUID, AND A CARTESIAN ELEMENT IN SAID LIQUID WHICH MAY BE MADE TO SINK IN SAID LIQUID BY INCREASING THE LIQUID PRESSURE AND TO RISE IN SAID LIQUID BY DECREASING THE LIQUID PRESSURE, THE IMPROVEMENTS COMPRISING PRESSURE ADJUSTING MEANS ON SAID CHAMBER OPERABLE EXTERNALLY OF THE LATTER FOR VARYING THE PRESSURE OF SAID LIQUID TO MAKE SAID ELEMENT SINK AND RISE, SAID PRESSURE ADJUSTING MEANS INCLUDING A FIRST PRESSURE ADJUSTING MEMBER FOR INITIALLY SETTING THE PRESSURE OF SAID LIQUID AT A GIVEN VALUE AT WHICH SAID ELEMENT HAS APPROXIMATELY NEUTRAL BUOYANCY IN SAID LIQUID AND A SECOND PRESSURE ADJUSTING MEMBER FOR THEREAFTER VARYING SAID PRESSURE OVER A GIVEN RANGE ABOUT SAID GIVEN VALUE. 